Would agree with you there Oldskool, though 'big strong hunting' greyhounds ain't that common.
For me constitution would have to be the overriding factor, good bone and feet.
I think it would also be a factor if..... you were adding to, or creating a lurcher, what type of greyhound, if greyhound at all.....?
Depending on what you want, the 'right type' of sight hound, would make a difference.
I've seen far to many 'un-interested' greyhounds to belive that any would be good for lurcher production and if size wasn't a factor, whippets or whippet/greyhounds IMO are a better bet.